There are locking systems (smart-entry systems) that detect when a person approaches or exits a vehicle, recognize the intention of the person to lock or unlock the vehicle door, and automatically control the locking and unlocking of the vehicle door. However, these systems lack convenience in that if the person has not been informed as to whether a vehicle door controlled by such a smart-entry system is locked or unlocked, ultimately the person must verify each time whether the vehicle door is locked or unlocked.
Patent Document 1 discloses a technique for wirelessly locking and unlocking a vehicle door from outside the vehicle based on a method for indicating the state of the vehicle door in a so-called keyless entry. It is proposed in this patent document that, when the vehicle door is locked or unlocked, the quantity or type of emitted light by the interior illumination, headlights, taillights, or the like is determined in correspondence with the brightness of the surroundings of the vehicle, and a light control signal is outputted; or the volume or tone of a buzzer is determined in correspondence with the brightness of the surroundings of the vehicle, and a sound control signal is outputted. Specifically, when the surroundings are bright, such as during daytime, the state may not be readily recognized via emitted light alone; therefore, the emitted light is minimized and a sound is produced by a buzzer. When the surroundings are dark, such as in the evening or at night, the buzzer is minimized and light is emitted.
Patent Document 2 discloses a system wherein the exterior part of a door handle grip part is composed of a light-permeable or transparent material, and the interior is provided with a light source. If applied to a smart-entry system, this configuration is able to indicate locking and unlocking in an easily visible location when a person enters or exits the vehicle.
Patent Document 1: Japanese Patent Application “kokai” No. 2000-45593 (Pages 4 through 5, FIG. 2)
Patent Document 2: German Patent No. 10060780 Specification (FIG. 2)